This invention is concerned with a machine for use in the manufacture of shoes, having a shoe support comprising a last pin on which a shoe, comprising a shoe upper on a last with an insole on the last bottom, can be supported, bottom up, a toe support for supporting the toe end of a shoe supported the by the last pin, and a shoe heel end positioning mechanism comprising a datum member engageable by the heel end of a shoe supported by the last pin for positioning said heel end in a direction extending lengthwise of the shoe, and also a heel seat height gauge device whereby the height of the bottom of such shoe in the heel seat region thereof can be set.
In recent years there has been a move to control more accurately the operating paths of tools for operating upon shoes and to this end it has become progressively more necessary for the positioning of the shoe to be achieved accurately within the machine of which such operating tools forms part. At the same time, the shoe supports are also used to provide e.g. dimensional information concerning the shoe which is held thereby, which information in turn can then be used in the control of the operating path of the tools.
One shoe support of the aforementioned type is described in U.S. Pat. No. 4,970,745, being a shoe support particularly useful for a machine for roughing side wall portions of shoes. In this shoe support the shoe is centralised with its heel-to-toe longitudinal axis coincident with a longitudinal centre line of the shoe support, so that the shoes are similarly oriented regardless of whether they are rights or lefts. Such a feature is wholly acceptable in the case of a roughing machine, but may not be so in the case of other machines, especially where only part of the shoe is being operated upon and a different parameter, e.g. the longitudinal centre line of a heel portion of the shoe, is to be aligned with the longitudinal centre line of the shoe support. Moreover, while, in the case of the aforementioned roughing machine, it is necessary to ensure that the shoe bottom is held in a desired heightwise position in order to ensure that the shoe side wall portions are consistently maintained in the correct relationship with the pre-programmed path of the roughing tool, nevertheless the path is in fact determined in accordance with the shoe position--dictated by fixed heel end and toe end height datums--rather than the position being determined by the tool path. In other shoe-making machines, by contrast, the tool path may be fixed, e.g. in the case of a lasting machine having wiper plates movable in a plane, and thus, it will be appreciated, the arrangement described above in respect of the roughing machine would not be suitable for use in a machine where the tool path is fixed.
In the operation of the aforementioned roughing machine, furthermore, it is necessary, at one stage in the progressive operation of the roughing tool, to move the shoe heel end positioning mechanism, which also serves a clamping function, to an out-of-the-way position. In order to enhance the stability of the shoe after the shoe has been positioned. During such stage, therefore, the last pin is tilted about a transverse axis, this tilting of the last pin serving to "lock" the last against the toe support. In the roughing machine, of course, the pressure applied by the tool to the shoe is directed laterally and the support arrangement described above has been found adequate to maintain the stability of the shoe against such pressure. Where, however, greater and/or differently directed forces are to be applied to the shoe, as e.g. in a lasting machine, especially during the initial engagement of the shoe bottom by the lasting tools where firm clamping of the shoe heel end is generally considered to be essential, the arrangement for the roughing machine would not be suitable, from the point of view of ensuring the stability of the shoe, and thus maintaining the desired orientation of its bottom.
Because, as already mentioned, the programmed path of the roughing tool is determined after the model shoe to be digitised has been positioned in the shoe support, effectively the various style features do not in any way affect the positioning of the shoe in the shoe support, but rather such features are readily accommodated in the programme. Such a relatively simple approach, it will be appreciated, cannot readily be followed in the case of a machine where the positioning of the shoe is dictated at least partly by fixed features of the machine. Nevertheless in terms of machine efficiency and enhanced quality of performance (in that setting the machine according to the particular shoe being operated upon becomes merely a matter of selection on the part of the operator) the ability to programme the machine setting is desirable.